1. Field of Invention
This invention relates generally to scales which provide a reading of body weight, and more particularly to a scale of this type which is selectively operable to provide a reading of muscular strength independent of body weight.
2. Status of Prior Art
Exercise and body development for maintaining fitness and in assisting in physical growth can be practiced at home. Thus, tension-resisting devices of various types are commonly used for the development of back, shoulder and arm muscles.
When undergoing a program of exercise, it is desirable to keep tabs on the effect thereof on the body weight of the exerciser. Thus, if one undertakes an exercise program with a view not only to gaining muscular strength but also toward reducing body weight, the increase in strength may be accompanied by a gain rather than a loss in weight. In some instances one seeks to increase body weight when following a program of muscular development. Hence, the correlation of changing strength to weight is of concern to the serious exerciser.
The use of a home or bathroom scale to measure body weight is commonplace. But the measurement of strength normally requires a separate scale. Thus, the patent to Newman, U.S. Pat. No. 2,784,592, discloses a muscle tester having a handle which is grasped by the user and pushed, the resultant force being indicated on a gauge.
To make it possible to use a conventional bathroom weighing scale as a hand grip testing device, Richard et al., in U.S. Pat. No. 3,848,468, provides a grip accessory that is attachable to a body weighing scale. This accessory includes a plunger which when pressed downwardly by a gripping action causes the dial of the scale to indicate the strength of the grip. In order to use the scale to measure body weight, the accessory must be detached therefrom and the scale placed on the ground.
Bradley et al., in U.S. Pat. No. 3,785,644, also uses a weighing scale to measure strength, and for this purpose an overhead bar is tied by ropes to the ground. The user, when raising the bar, stands on the weighing scale between the ropes. In this arrangement, in order to measure strength, after the individual steps on the scale it must then be zero set, so that regardless of the user's weight, the scale reads zero until he lifts the bar and imposes a force on the spring-operated scale that causes it to read above zero.
Hence, should the user, after measuring his strength, now wish to measure his weight, the scale must be reset so that it reads zero in the absence of body weight. This requirement represents a practical drawback, particularly since as the user changes weight in the course of an exercise program, it becomes necessary to provide a different zero setting each time the scale is used to measure strength.